1. Field of the Invention
The present invention relates to electrical contacts and methods of manufacturing electrical contacts. More specifically, the present invention relates to electrical contacts with solder members and methods of attaching solder members to electrical contacts.
2. Description of the Related Art
It is well known to attach solder to electrical contacts of an electrical connector. The solder is used to form an electrical and mechanical connection between the electrical contact and an electrical pad on a printed circuit board.
U.S. Pat. No. 6,969,286 discloses a conventional method of attaching solder to a contact. FIG. 33 shows a portion of a ribbon 140 of such contacts 110 with solder 120. The solder 120 is attached to the contact 110 by inserting the solder 120 between opposing arms in the tail 113 of the contact 110 and crimping the solder 120 so that the solder 120 is located on two sides of the contact 110. The contact 110 includes a body 112 connecting the head 111 and the tail 113.
To allow contact 110 to be removed from ribbon 140 without dislodging the solder 120, the shoulders 112a of the body 112 of contact 110 are connected to the ribbon 140 at breakoffs 141, and the distance between the shoulders 112a and the solder 120 must be at least some fixed distance. The contact 110 cannot be connected at the bottom of the tail 113 of the contact 110 because of the arm design that holds the solder 120. Because the contacts 110 are attached at the shoulders 112a of the body 112, the width of the contacts 110 and the pitch between contacts 110 cannot be smaller than some fixed distance. The contacts 110 cannot be made smaller because there would be no room to locate the shoulders 112a with the breakoffs 141. The body 112 of the contact 110 is held in a core in an electrical connector. The contact 110 cannot be inserted into the core of the electrical connector past the shoulders 112a, even if each of the cores of the electrical connector includes a relief or a recess. Because the contact 110 cannot be inserted further, the distance between the bottom of the electrical connector and the bottom of the contact 110, including the solder 120, cannot be smaller than some fixed distance. Because this distance cannot be made smaller than a fixed distance, the stack height of the electrical connector (the minimum distance between two printed circuit boards that are joined together by a mated pair of electrical connectors) that uses the contact 110 cannot be made smaller than a fixed height.
U.S. Patent Application Publication No. 2008/0108255 discloses another method of attaching solder to a contact. FIG. 34 shows a carrier 240 of contacts 210 with solder 220. The solder 220 is inserted into an aperture 216 in the tail 213 of the contact 210 and then cold-formed to secure the solder 220 to the contact 210 so that solder 220 is formed mainly on only one side of the contact 210. The solder 220 has a width smaller than the width of the shoulders 212a. The bodies 212 of the contacts 210 are connected to each other at shoulders 212a, with the shoulders 212a of the contacts 210 on the ends connected to breakoffs 241 of the carrier 240. FIG. 35 shows a single contact 210 with the solder 220. The center portion of the solder 220 is pushed into the aperture 216 of the contact 210, which forms depression 222, as shown in FIG. 36. As seen in FIG. 37, the aperture 216 has a rectangular shape. In this arrangement, the solder 220 is attached to the contact 210 only at a single point of attachment. As seen in FIG. 38, the solder 220 can be easily rotated with respect to the contact 210. The contact 210 cannot be inserted into the core of an electrical connector past the shoulders 212a, even if the each of the cores of the electrical connector includes a relief or a recess. Because the contact 110 cannot be inserted further, the distance between the bottom of the electrical connector and the bottom of the contact 210, including the solder 220, cannot be smaller than some fixed distance. As with an electrical connector using the contact 210, because this distance cannot be made smaller than a fixed distance, the stack height of the electrical connector (the minimum distance between two printed circuit boards that are joined together by a mated pair of electrical connectors) that uses the contact 210 cannot be made smaller than a fixed height.
To allow the machinery required to the remove carrier 240 at breakoffs 241 and to be able to later separate the contacts 210 from each other by separation cuts at the shoulder 212a, the contacts 210 are attached at the shoulders 212a, with the shoulders 212a of the contacts 210 on the ends connected to breakoffs 241 of the carrier 240, and the distance between the shoulders 212a and the solder 220 must be at least some fixed distance.
Because the contacts 210 are attached at the shoulder 212a of the body 212, the width of the contacts 210 and the pitch between contacts 210 cannot be smaller than some fixed distance. The contacts 210 cannot be made smaller because there would be no room to locate the shoulders 212a with the breakoffs 241.
The solder 220 is not reliably secured to the contact 210, which allows the solder 220 to rotate out of position or become dislodged during shipping, handling, or assembly. As seen in FIG. 36, the single point of attachment at the aperture 216 results in the solder 220 being easily sheared-off and easily pushed-out. Because the aperture 216 is nearly a square shape, the solder 220 is minimally prevented from rotating.